For example, if contents used for a television broadcast are generated, a process that generates the contents used for the broadcast is executed by transmitting images captured by multiple video cameras disposed at multiple different positions are transmitted to an editing studio via a network, and by executing an editing process which generates an image or the like in which multiple images are combined or one image is selected from images captured by multiple cameras in an editing apparatus in the editing studio.
In such an editing process, it is necessary to exactly discriminate what timing each image is captured individually by each camera. As information for this, a time stamp indicating a capturing time or the like is set in the image captured by each camera, and the editing apparatus executes the editing process with reference to the time stamp, thereby enabling the image captured by each camera to be edited without any time difference.
However, the time stamp is set by using a clock signal generated by a clock embedded in each apparatus connected via a network. If there is a phase difference or a frequency difference in the clock signal of apparatuses connected via the network, a difference occurs in the time stamp set in each apparatus.
In order to correct the clock signal difference between apparatuses connected via the network, a clock synchronizing process which transmits and receives a synchronization packet between the devices connected via the network is executed. For example, PTL 1 (Japanese Unexamined Patent Application Publication No. 2010-190635) in the related art discloses the synchronizing process between multiple communication apparatuses connected via a packet transmission network such as Ethernet (a registered trademark).
PTL 1 discloses a configuration where the clock synchronizing process is executed between a master and a slave by transmitting and receiving a packet between a master apparatus and a slave apparatus that execute the synchronizing process, and performing an analysis to which transmission time information and reception time information which are recorded in the received packet is applied.
However, in a communication process via the network, a communication delay occurs. This delay amount is not constant and varies depending on network load situations. In other words, jitter which is a fluctuation of delay time occurs. For example, the synchronizing process by synchronization packet transmission and reception such as that described in the above-described PTL 1 can be executed with high precision when the network delay is constant, but when such jitter occurs, there is a problem that it is difficult to execute a highly precise synchronizing process.